In conventional flashlights, manually-operated mechanical switches function to turn the flashlight "on" and "off." When turned "on," battery power is applied through the closed switch to a light bulb, the amount of power then consumed depends on how long the switch is closed. In the typical flashlight, the effective life of the battery is only a few hours at most. Should the operator, after using the flashlight to find his/her way in the dark or for any other purpose, then fail to turn it off, the batteries will, in a very short time, become exhausted. Should the flashlight be left in a turned-on and exhausted condition for a prolonged period, the batteries may then leak and exude corrosive electrolyte that is damaging to the contact which engages the battery terminal as well as the casing of the flashlight.
When the flashlight is designed for use by a young child the likelihood is greater that the flashlight will be mishandled, because a young child is prone to be careless and forgets to turn the flashlight "off" after it has served its purpose. Because of this, a flashlight may be left "on" for days, if not weeks, and as a result of internal corrosion may no longer be in working order when the exhausted batteries are replaced.
Flashlights designed for young children are sometimes in a lantern format, with a casing made of strong plastic material that is virtually unbreakable, the light bulb being mounted within a reflector at the front end of the casing and being covered by a lens from which a light beam is projected. A U-shaped handle is attached to the upper end of the casing, with mechanical on-off slide switch being mounted on the handle, so that a child grasping the handle can readily manipulate the slide actuator with his/her thumb.
With a switch of this type on top of a flashlight handle, when the slide actuator is pushed forward by the thumb, the switch "mechanically" closes the circuit and the flashlight is turned "on" and remains "on" until the slide actuator is pulled back to the "off" position and the circuit is opened. It is this type of switch in the hands of a child that is most likely to be inadvertently left "on."
To avoid this problem, many flashlights include, in addition to a slide switch, a push button switch which keeps the flashlight turned on only when finger pressure is applied to the push button. It is difficult for a young child who wishes, say to illuminate a dark corner in the basement of his home for about 30 seconds, to keep a push button depressed for this period. It is therefore more likely that the child will actuate the slide switch to its permanently-on position, for this requires only a monetary finger motion.
It is known to provide a flashlight with a delayed action switch which automatically turns off after a pre-determined interval. The Mallory U.S. Pat. No. 3,535,282 discloses a flashlight that is automatically turned off by a delayed action mechanical switch assembly that includes a compression spring housed in a bellows having a leaky valve, so that when a switch is turned on manually, this action serves to mechanically compress the bellows which after a pre-determined interval acts to turn off the switch.
A similar delayed action is obtained in a flashlight for children marketed by Playskool Company, this delayed action being realized by a resistance-capacitance timing network which applies a bias to a solid-state transistor switch after 30 seconds or so to cut off the transistor and shut off the flashlight. Also included in the prior art, is a flashlight previously sold by Fisher-Price using an electronic timing circuit to simply turn off the flashlight after about 20 minutes.
It is also known, e.g. as disclosed in U.S. Pat. No. 4,875,147, to provide a mechanical switch assembly for a flashlight which includes a suction cup as a delayed action element whereby the flashlight, when momentarily actuated by an operator, functions to connect a battery power supply to a light bulb, and which maintains this connection for a pre-determined interval determined by the memory characteristics of the suction cup, after which the connection is automatically broken.
U.S. Pat. No. 5,138,538 discloses a flashlight having the usual components of a battery, and on-off mechanical switch, a bulb, and a hand-held housing, to which there is added a timing means and a circuit-breaking means responsive to the timing means for cutting off the flow of current to the bulb, which further has a by-pass means, preferably child-proof, to direct electric current to the light bulb regardless of the state of the timing means. The patent also provides for the operation of the device may be further enhanced by making the by-pass means a mechanical switch connected so as to leave it in series with the mechanical on-off switch. Furthermore, the patent discloses a lock or other "child-proofing" mechanism may be provided to ensure that the by-pass is disabled when the flashlight is switched off.
Most conventional flashlights, like those described above, are actuated by mechanical push or slide button-type switches requiring, of course, mechanical implementation by an operator. Over time, the switch suffers "wear and tear" which impairs operation of the flashlight as a result of, for example, repeated activations by the operator and/or due to the fact that the switch has been left "on" for a prolonged period of time. In addition, such mechanical switches are vulnerable to the effects of corrosion and oxidation and can cause said switches to deteriorate and to become non-functioning. In addition, these prior art devices having these mechanical switches are generally "dumb," i.e. they do not provide the user with convenient, reliable, and affordable functionalities which today's consumers now demand and expect.
The prior art switches typically provide two basic functions in prior art flashlights. First, the mechanical switches act as actual conductors for completing power circuits and providing current during operation of the devices. Depending upon the type of bulb and wiring employed, the intensity of electrical current which must be conducted by the switch is generally quite high leading to, after prolonged use, failure. Second, these mechanical switches must function as an interface between the device and its operator, i.e. the man-machine-interface ("MMI") and necessarily requires repeated mechanical activations of the switch which over time mechanically deteriorate.
Also, currently the electrical switches used in buildings/houses for control of lighting systems are of the conventional type of switches which must conduct, i.e. close the circuit, upon command, thus also providing the MMI. These prior art switches suffer from the same disadvantages as the switches described above in relation to portable electronic devices, like flashlights. Moreover, the switches are relatively dumb in most cases and do not provide the user with a variety of functions, e.g. but not limited to timing means to enable a user, for example, a shop owner or home owner to designate a predetermined shut off or turn on point in time.
There is a need for inexpensive, reliable, and simple intelligent electronic devices which provide increased functionality and energy conservation.